This invention relates to an image forming apparatus, an image processing apparatus and an image printing system used in an electrophotographic printer, copier, facsimile machine or combined machine. In particular, this invention relates to an image forming apparatus and an image printing system capable of borderless printing.
In an image forming process, a toner having been transferred to a recording medium is fixed to the recording medium by means of a fixing device. In the fixing device, there may be cases in which the recording medium is not well separated from a fixing member (for example, a fixing roller). Therefore, a separating claw is provided in contact with the surface of the fixing member so that the recording medium can be peeled off and separated from the fixing member, as disclosed in Japanese Utility Model Laid-Open Publication No. 7-34450 (page 3, FIG. 1). Further, no toner image is formed on a leading end of the recording medium. Further, a non-printing area (i.e., a margin on which no toner image is formed) is provided on the leading end of the recording medium, so that the recording medium can be separated from the fixing member due to the firmness of the leading end of the recording medium.
Recently, there is a need for a function to print a borderless image without leaving the non-printing area on the leading end of the recording medium (i.e., a borderless printing). If the borderless printing is performed, since the non-printing area is not provided on the leading end of the recording medium, the firmness of the leading end of the recording medium decreases, and therefore the recording medium may not be peeled off and separated from the fixing member. In such a case, the recording medium may be wound around the fixing member. For that occasions, the above described separating claw (i.e., a separating means) is provided in contact with the fixing member, and the separating claw peels off and separates the leading end of the recording medium from the fixing member.
However, if the separating claw is provided in contact with the fixing member for peeling off and separating the recording medium from the fixing member, a scratch may be formed on the surface of the fixing member. In such a case, when the toner image is fixed to the recording medium, the scratch may cause a strip or a pattern to be formed on an image, and therefore the image quality may be degraded. Accordingly, the provision of the separating claw for separating the recording medium from the fixing member has a problem.